Beneficiation of lubricants



Patented July 1942 UNITED STATES PATENT" OFFICE j I I I 2,290,859

WI 2E1: 23133213331...

Heights, Ohio, assignors to The Standard Oil Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Application April 13, 1940,

Serial No. 329,523

8 Claims. (Cl. 252-49) Where a lubricating oil is subjected to drastic high temperature usage, as for instance in an internal combustion engine, it tends to change in nism of the change is obscure and involves complex factors. By some writers the action has been ascribed to oxidation. However, the matter is not so simple as this, and the degradation can be brought about'in the absence of oxygen. We have now found that by subjecting an oil to the action of certain material, the degradation hydrocarbon, Z is hydrogen or alkyl or aryl hydrocarbons or mixtures thereof, X is oxygen or sulphur, and M is phosphorus or phosphorus yiscosity and lubricating activity. The'mechatendency of the oil in drastic high temperature.

usage is arrested, thematerial however, although very effective, has a side action of prima facie making the oil corrosive on metal surfaces which it lubricates, but as a part of the invention this undesired side tendency is corrected and controlled'by conjoined action of another material which we,have found' particularly to bring about such results; and thelubricant as a whole is thus of outstanding advantage for severe high temperature usage. Y

To the accomplishment of the foregoing and f related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principle of the invention.

may .be employed.

In accordance with the invention, an oil of lubricating viscosity, high or low in accordance with the particular duty intended, and for instance being in general of 45 to 200 viscosity, Saybolt Universal at 210 F., issubjected to the action of a small amount of a very active agent maintaining the oil against viscosity change in degradation change otherwise occurrent, and the side effect. of corrosive action on metals with for instance 0.001-5 per cent, and generally amounts less than 2 per cent are satisfactory. The metal corrosion inhibiting agent is an organic ester or thioester of a phosphorus acid, i. e. phosphorus and phosphoric acids-such esters having the general formula Z-X7M z-x 4 wherein R is an alkyl, aryl, alkaryl or c'ycloparaihn run in a test at 350? F. for 42 hours shows a viscosity of 381, lacquer formation 2.1 Mg, and appearance rating B minus, whereas the oil without the addition agents and run at the same temperature for the same length of time changes in viscosity to 4'79, and lacquer formation is 7.9, and the appearance rating C plus.

As another example: In a lubricating oil of -Mid-Continent stock and having a gravity 389 Saybolt Universal at 100 F., there is incorporated 0.05 per cent of ordinary phosphorus and 0.15 per cent of tricresyl phosphite. This lubricant run in test at 350 F. for 42 hours shows a viscosity 403, lacquer formation 4.2 Mg, and appear-"' ance rating 0', whereas the oil without the addiperature usage, which comprises subjecting the tion agents and tested at the same temperature and for the same length of time changed in viscosity to 630 and showed lacquer formation 46.3 Mg, and appearance rating E minus.

As another example: In a similar lubricating so far as we are aware it has not been known to treat oil with an active agent otherwise occasioning corrosion of metal'surfaces, and at the same .time guard such metal against untoward action.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any ofthe following claims, or the equivalent of such, be employed.

We'therefore particularly int out and distinctly claim as our invention: I 1. A process of increasing the durability of 1 mineral oils of lubricating viscosity in high temoil to the action of a small amount of phosphorus and inhibiting metal corrosion of the phosphoru by a small amount of tricresyl phosphite.

2. A process of increasing the durability of 2 I a mineral oils of lubricating viscosityin high temperature usage, which comprises subjecting the oil to the action of a small amount of phosphorus and inhibiting metal corrosion of the phosphorus by a small amount of tricresyl phosacid from the group consisting of phosphorus and phosphoric acids.

. 5. A lubricant comprising a mineral oil oilubricating viscosity, and a small amount of phosphorus and a small amount oi tricresyl phosphite.

- lubricating viscosity. and a small amount or ;phorus acid having the general 8. A lubricant comprising a mineral oil of phosphorus and a small amount of tricresyl phosphate.

'i. A lubricam comprising a mineral oil of lubricating viscosity, and a small amount or phosphorus and a small amount or tricresyl thiophosphate.

8. A lubricant comprising a oil of lubricating viscoflty, and a small amount 01 phosphorus and a small amount or an ester of a-phosformula n-x I 1-K? z-x 1 wherein R is an alkyl, aryl, alkaryl or cycloparaiiin hydrocarbon. Z is hydrogen or alkyl or aryl hydrocarbons or mixtures thereof, X is oxygen or sulphur, and M is phosphorus or phosphorus monoxide. V

ROBERT E. BURK. EVEREI'I C. HUGHES. 

